1. Field of the Invention
The present invention relates to a steering system.
2. Description of Related Art
A steering system described in Japanese Patent Application Publication No. 2005-138758 (JP 2005-138758 A) includes a lower column, an upper column that can telescopically and slidably extend and contract with respect to the lower column, and a lower shaft and an upper shaft that are rotatably supported in the lower and upper columns, respectively. At the time of vehicular secondary collision, the upper shaft slides with respect to the lower shaft.
A stopper member is provided at a rear end of the outer column. The stopper member includes a support pin protruding from the stopper member toward opposite sides in a lateral direction and an abutting contact portion extending generally downward from the support pin. An opening is formed in each of the lower and upper columns such that the abutting contact portion of the stopper is inserted through the openings. A pair of support wall portions is formed on the lower column such that each of the support wall portions is located adjacently to the opening in the lower column. In each of the support wall portions, a support groove is formed which supports the support pin. A spring pin is inserted between each of the support wall portions and the stopper member and is rotatable around the spring pin.
When the upper column is pulled out, a front edge of the opening in the upper column comes into abutting contact with the abutting contact portion of the stopper member. When the upper column is pushed in, a rear edge of the opening in the upper column comes into abutting contact with the abutting contact portion of the stopper member.
In the steering system described in JP 2005-138758 A, at the time of a secondary collision, an impact load acting toward the front of a vehicle is imposed on the support pin, and the support pin is sheared to slip out from the support grooves. At this time, the stopper member rotates to cause the abutting contact portion to slip out from the opening in the upper column. Thus, when an attempt is made to pull out the upper column after the secondary collision, the upper column is detached from the lower column because the edges of the opening do not come in abutting contact with the abutting contact portion.